Ettore bellini



1929- E. BELLINI 1,723,461

RADIOGONIOMETER Filed March 4, 192'? lNVENTOR ETTORE BELLNI 4%,]? &

NEY

Patented Aug. 6, 1929.

E'ITORE BELLINI, OF PARIS, FRANCE.

RADIOGONIQIYIETER.

Application filed. March 4, 1927, eerie No. 172,816, and. in France March 4, 1926.

In order to eliminate doubt as to direction of incoming waves, in indications obtained with radio goniometers, it is general practice to have recourse to the method consisting in superposing the action of a vertical antenna upon that of the coil or loop, as disclosed in French patent #387,983, dated March 7th, 1908. In order to avoid the necessity of mounting a separate vertical antenna, recourse is often had to the loop or coil itself, indeed, the latter is then used both as a loop and as a vertical antenna. A method with this end in view has been disclosed in French patent #567,587, dated June 11,

' 1923, and the two additions thereto, #29,-

671 of March 19, 1924 and #230,309, dated November 20, 1924. One object of this invention is to provide a radio gouiometer in which an antenna of the loop or coil type serves the combined functions of a coil and a vertical antenna.

A further object is to modify the directional characteristics of a coil type antenna in such manner that the sense of direction of incoming electrical waves may be determined. A further object is to provide a stopper circuit in connection with the loop, so arranged that the loop itself serves as the self-inductance coil of the stopper circuit. A still further object is to provide two stopper circuits. for the antenna current, these circuits being symmetrical or balanced with respect to the loop and the ground connection.

The invention is shown diagrammatically in the z-iccompanying drawing in which,

Fig. 1 shows the coil and connection used in the above French patent and additions thereto, and

Fig. 2 shows diagrammatically the loop and connection used in the present invention.

As shown in Fig. 1 and the above French patent, I provide a stopper circuit between the middle point (C), of the loop and ground, said stopper circuit consisting of the condenser (Ce) connected in parallel with the inductance coil (A), together with a variable resistance (R), inserted between the inductance and the ground. The point (d) of the loop condenser (D) is connected with the grid of any suitable amplifier (7)), the filament battery of said amplifier being connected to ground as shown. In the presinvention 1 have replaced stopper circuit shown in Fig. 1, in the following The coils (0) represent the inductance of the coil or loop, or they may be extra induc tances added in the coil or loop. One hori zontal side of the coil or loop is comprised of the inductance coil (L).

Between the midpoints of the coil (L) and the opposite side of the loop (O), a variable condenser (Cd) is connected and between the midpoint of the coil (L) and ground a variable resistance (R) is inserted. A switch (8) is inserted in the wire which connects the midpoint (CZ) directly with the ground as shown.

A variable condenser nected across the vertical limbs of the loop (T) is conand one plate of the condenser is connected to the grid of amplifier (7)) as shown.

will be seen that whereas in F1g. 1, one stop circuits.

By adjusting the condenser (Cd) to make the stopper circuit resonant, a path oi: high impedance is provided for the antenna current to ground.

Since in each of these circuits, a path of high impedance has been provided for the antenna current, the points (C) and (Cl) respectively are held at maximum potential with respect to ground.

In the use of the loop shown in Fig. 2, the switch is closed, when the loop is used to determine the line of direction of the incoming signal.

In this case, since the midpointof the loop is directly grounded, the loop has no eltect as a vertical antenna and the sense of direction from which the incoming wave is coming may not be determined.

determine the sense of direction of the incommg wave, the switch (.9) 1S opened and the stopper c1rcu1t tuned by the condenser The antenna effect of the loop now comes into play, and by suitably varying the resistance (R), the antenna effect may be varied, so that the antenna effect and the loop effect neutralize each other and produce a oint v.

minimum signal a no signal at all, when the loop is rotated in the usual manner. This will indicate the absolute direction from which the incoming wave is proceeding. The inductance (L) will usually be chosen to have a large value com pared to the inductance of the loop itself or to the loop taken in connection with the inductance of the coil (0).

What I desire to secure by Letters Patent of the United States is 1. In a radiogoniometer, a loop circuit tuned to, incoming signals, and inductance connected in parallel with said loop circuit, a variable resistance connecting the midpoint of said inductance to ground, and a variable condenser connected between the midpoint of the loop and that of the in ductance.

2. In a radiogoniometer, a loop antenna, a condenser for tuning said loop to incoming ,waves, an inductance coil connected in par allel with said loop, a variable condenser connected between the midpoints of the loop and the inductance coil, an adjustable resistance connected-between the midpoint of said coil and; the ground, and. an-amplifier tube having its grid connected to one plate of the loop tuning condenser and also having its filament connected to ground.

n a r cio 'oniomet 1- an eec'ric 3 I al g e, l t ally balanced loop circuit tuned to signal waves for obtaining the line of direction of the source of said waves, and means for electrically unbalanci-ng said loop circuit to determine the absolute direction of the source of signal waves, said means comprising an inductance connected in parallel with saidloop, a variable resistance connecting the midpoint of said inductance to ground, and

a variable condenser connected between the midpoint of the loop and that of the in ductance.

4. In a radiogoniometer including thermionic tubes and filament heating batteries therefor, a loop antenna having a tuning condenser in series therewith, means for electrically balancing said loop including a grounded connection to the midpoint of the loop and also to the filament heating battery, and means for unbalancing the loop to obtain unidirectional elfects including an inductance coil connected across the loop, a variable condenser connected between the midpoints of the loop and. the coil for varying the amount of unbalance, and an adjustable resistance connecting the midpoint of said coil to ground.

5. A uni-directional antenna system, comprising a loop circuit having means for tuning to incoming signals, an inductance-connected in parallel with said loop circuit, a variable condenser connected between the midpoints of said loop and said inductance, an adustable resistance connecting the midpoint of said inductance to ground, and a switch shunting said condenser and resist ance, the arrangement being such that when said switch is closed and the loop rotated until maximum signals are obtained, the plane of the loop will indicate the line of direction of the source of incoming signals, and when rotated to the point of minimum signal the absolute direction will be determined.

In testimony whereof, I hereunto subscribe my name.

ETTORE BELLIN I. 

